An unusual 17α,21β(H)-bacteriohopanetetrol in Holocene sediments from Ace Lake (Antarctica)

Whilst investigating the intact biohopanoid (bacteriohopanepolyol, BHP) distribution in Holocene sediments from Ace Lake (Antarctica), we found αβ-bacteriohopanetetrol in sediments aged up to 9400 yr BP. To our knowledge, this is the first time that an intact polyfunctionalised BHP with the “geological” 17α,21β(H) configuration has been identified in a sediment. Previously, the structure had only been observed in species of the nitrogen fixing bacterium Frankia. Its presence in the sedimentary environment has implications for the interpretation of hopanoid ββ/αβ ratios in the geological record.